Dishwasher machine comprising a sorption drying device provided with a sorption material adapted in terms of weight to the wetting quantity in the washing compartment

ABSTRACT

A dishwasher having a washing compartment; a drying device to dry washed items, wherein the drying device has a sorption compartment to hold reversibly dehydratable sorption material; and an air-guiding air ducting channel between the drying device and the washing compartment to generate an air exchange between the washing compartment and the sorption compartment. In the sorption compartment, a weight of the reversibly dehydratable sorption material that is provided to absorb a moisture quantity conveyed by the air exchange is such that the moisture quantity absorbed by the reversibly dehydratable sorption material is less than a liquid quantity applied to items to be washed.

The present invention relates to a dishwasher machine, in particular a household dishwasher machine, having at least one washing compartment and at least one drying device for drying washed items, it being possible for the drying device to have at least one sorption compartment for receiving reversibly dehydratable sorption material, in particular zeolite, and at least one air-guiding, air ducting channel between the drying device and the washing compartment for generating an exchange of air between the washing compartment and the sorption compartment.

Dishwasher machines with a so-called sorption column for drying dishes are known from DE 103 53 774 A1, DE 103 53 775 A1 or DE 10 2005 004 096 A1, for example. Here, in the “dry” sub-program step of the respective washing program of the dishwasher machine for drying dishes, moist air from the washing compartment of the dishwasher machine is conveyed through the sorption column and through its reversibly dehydratable desiccant by means of a blower, and moisture is removed from the through-flowing air due to condensation. For regeneration, that is to say desorption of the sorption column, its reversibly dehydratable desiccant is heated up to very high temperatures. As a result, water stored in this material emerges as hot water vapor and due to an airflow generated by the blower is conveyed into the washing compartment. This enables washing liquor and/or dishes located in the washing compartment, as well as the air in the washing compartment to be heated up. Such a sorption column has proved to be very advantageous for energy-saving and gentle drying of the dishes. In order to prevent local overheating of the desiccant during the desorption cycle, a heater is arranged in the direction of the airflow upstream of the air inlet of the sorption column, as for example in DE 10 2005 004 096 A1. In spite of this “air heating” during desorption, in practice it is difficult to dry the reversibly dehydratable desiccant in an adequate and faultless fashion.

The object underlying the invention is to provide a dishwasher machine, in particular a household dishwasher machine, with which a much improved sorption and/or desorption result is achievable for the reversibly dehydratable desiccant of the sorption unit of its sorption drying device.

This object is achieved by a dishwasher machine of the type described in the introduction in that in the sorption compartment the weight of reversibly dehydratable sorption material provided for the absorption of a quantity of moisture conveyed by the air exchange is such that the quantity of moisture absorbed by the sorption material is less than the quantity of liquid applied to the items to be washed, in particular the quantity of liquid applied in a clear rinsing step.

An efficient air moisture bond is facilitated when the sorption material used is small by adapting the weight of the sorption material in the sorption compartment so that said sorption material takes up only a portion of the total weight of liquid, which is less than the total weight of liquid applied to the items to be washed. This allows a compact form of construction to be achieved for the sorption compartment.

At the same time, this ensures that the energy consumption for complete regeneration of the sorption material by heating by means of a heater can be reduced, since in fact only a sufficient, adapted or measured amount of sorption material is heated up for faultless drying of the washed items.

According to a first expedient development of the invention, the weight of reversibly dehydratable sorption material expediently provided in the sorption compartment is such that the amount of moisture absorbed by the reversibly dehydratable material essentially corresponds to the wetting quantity with which the washed items are wetted at the end of the clear rinsing step. In this case the wetting quantity, in particular, is the amount of liquid which, at the end of a clear rinsing step in which the already washed items were treated with water displaced by surfactant, adheres to the washed items, the basket for holding the dishes and/or the inner walls of the washing compartment and does not flow away under gravitational force to the base of the washing compartment. This adaptation of the weight of sorption material results in its moisture absorption capacity being sufficient to more or less completely bind or take up this wetting quantity in the sorption material by means of the air exchange.

Preferably, the weight of sorption material placed in the sorption compartment is such that the amount of moisture absorbed corresponds to between 4% and 25%, in particular 5% to 15% of the amount of liquid applied to the items being washed.

Advantageously, a weight of between 0.2 kg and 5 kg, in particular between 0.3 kg and 3 kg, preferably between 0.5 kg and 2.5 kg of reversibly dehydratable sorption material is present in the sorption compartment.

According to an expedient embodiment, the sorption compartment can be provided in a base assembly underneath the base of the washing compartment. This allows an adequate amount of sorption material to be compactly accommodated in the dishwasher machine, so that no constructional space is wasted in the region of the side walls of the washing compartment. The internal and external dimensions of the dishwasher machine therefore remain largely unchanged.

According to an expedient embodiment, the drying device can be connected to at least one outlet and at least one inlet of the washing compartment via at least one air ducting channel. This enables air to circulate in the closed circuit.

In particular it can be useful if the air ducting channel is more or less arranged outside the washing compartment, so that the useful space inside the washing compartment is maintained, that is to say not reduced.

In particular, provision can be made for the outlet-side tubular section of the air ducting channel to be connected to at least one inlet of the washing compartment in its region near the base. This is expedient if the sorption compartment is housed in the base assembly of the dishwasher machine. In this way, the outflow path for the dried air from the sorption compartment up to the inflow into the washing compartment of the dishwasher machine can be kept short, so that undesirable heat losses are largely avoided.

In particular, provision can be made for the inlet-side tubular section of the air ducting channel to be connected to at least one outlet of the washing compartment above its base, in particular in its region close to the top cover. This largely prevents spray water from a spray device in the washing compartment, for example, during the washing or clear rinsing cycle or intermediate rinsing cycle from entering the inlet opening of the inlet-side tubular section of the air ducting channel. This would otherwise lead to undesirable partial or complete saturation of and damage to the sorption material in particular impairment or even damage to the sorption material with regard to its original sorption and/or desorption properties, and make this partially or completely unusable for drying moist air from the washing container.

Furthermore, if necessary it can be advantageous if the inlet-side tubular section of the air ducting channel enters the sorption compartment of the drying device in the region close to the base in such a way that its inflow direction is deflected, in particular, by 90° into the preferably vertical through-flow direction of the sorption compartment. On the one hand this allows the moist air to be led out from the washing compartment via at least one inlet-side tubular section of the air ducting channel which is arranged on one side wall and/or rear wall of the washing compartment. On the other hand, the outlet-side tubular section of the air ducting channel can to a great extent run in a straight line between the outlet opening of the sorption compartment and the inlet opening of the washing compartment and be kept comparatively short. This is particularly advantageous when the outlet-side tubular section of the air ducting channel is connected to at least one inlet of the washing compartment in the region near its base. The outlet-side tubular section of the air ducting channel can then lead into an opening in the base of the washing compartment, for example. As a result, heat losses, in particular during desorption of the sorption material, can largely be avoided since the air heated up during desorption, which leaves the sorption compartment can flow largely without path loss, that is to say directly into the washing compartment. Consequently the efficiency of the sorption drying device is improved, particularly during desorption.

According to a further expedient development, viewed in the flow direction of the airflow, at least one blower for generating the airflow can be provided upstream of the drying device. This facilitates particularly effective forced ventilation of the sorption material.

According to a further expedient development, viewed in the flow direction, at least one associated heating element, in particular electrical heating element, can be provided for desorption between the blower and the drying device. This facilitates regeneration of the sorption material so that it is largely regenerated and made available for drying the washed items in the next dishwashing cycle.

In particular, viewed in the flow direction, it can be useful if, in the sorption compartment, upstream of its sorption unit containing the reversibly dehydratable sorption material, at least one heating element, in particular an electrical heating element, is provided for desorption of said sorption material as a constituent element of the sorption compartment. As a result, air heating is provided, that is to say hot air can flow through the sorption material in a more or less regular manner. In this way, so-called “hot spots”, that is to say local overheating points in the filled volume of the sorption material are largely avoided.

According to an expedient development, the drying device has at least one sorption unit with reversibly dehydratable dry material or desiccant, in particular a fixed bed of zeolite or a zeolite packing. A zeolite packing is, in particular, formed by loose zeolite granular material, preferably in the form of globules. The desiccant or sorption material having a largely uniform thickness is preferably accommodated in a container or housing of the sorption unit. At its air inlet opening and/or air outlet opening the container of the sorption unit is preferably delineated or covered in each case by at least one screen. In a practical way, this facilitates compact support for the sorption material, and at the same time adequate air penetration, so that the sorption material can adequately absorb moisture from through-flowing air by condensation and also again release or desorb stored moisture to through-flowing air by heating.

Other developments of the invention are described in the sub-claims.

The invention and its developments are explained in further detail below with the aid of a single FIGURE.

The single FIGURE shows schematically a dishwasher machine GS with a washing compartment SB and a sorption drying system TS which is preferably provided externally, that is to say outside the washing compartment SB of the dishwasher machine GS. As main components it includes an air ducting channel VK, at least one blower or a fan GB, as well as a drying device TE. One or more mesh baskets GK for holding and for washing dishes for example are accommodated in the washing compartment SB. The drying device TE is connected via the air ducting channel VK to at least one outlet EL and to at least one inlet AL of the washing compartment SB. In this case the air ducting channel VK is arranged largely outside the washing compartment SB. In detail, the inlet-side tubular section RA1 of the air ducting channel VK is connected to the outlet EL of the washing compartment SB in its region close to the cover or upper region which is at a distance from the base of the washing compartment. The outlet-side tubular section RA2 of the air ducting channel VK leads to the inlet AL of the washing compartment SB in its region near the base. In this way, air can be guided from the inside of the washing compartment SB via the air ducting channel VK to the drying device TE, for example during a drying step of a dishwashing program, and, then dry, from said drying device back into the washing compartment SB, that is to say circulate through the sorption drying system TS. Due to the air inlet in the upper region of the washing compartment SB, this more or less prevents water from the sump (omitted in the FIGURE for the sake of clarity) in the base of the washing compartment or from its water spraying system WS, reaching the air ducting channel and the sorption compartment BEH of the drying device TE, which at that point would otherwise make the sorption material unduly moist and unusable.

Advantageously, here in the exemplary embodiment, the drying device TE is accommodated in a base assembly or substructure BG underneath the base of the washing compartment SB. It is constructed as a so-called sorption column. In the common housing or container BEH, said sorption column includes at least one heating element HZ and, downstream in the direction of flow, a sorption unit SE which is filled with a reversibly dehydratable sorption material, such as zeolite ZEO, for example. The sorption unit contains, in particular, a fixed bed of sorption material, preferably a fixed bed of zeolite, as a molecular screen or a loose filling of sorption material, preferably zeolite filling. A sorption material filling, in particular a zeolite filling, is in particular, formed from loose granular material or other particles, preferably zeolite particles, preferably in globular form. The desiccant or sorption material is preferably accommodated as a single layer or multiple layers with more or less identical layer thickness in the container or housing BEH of the drying device TE in the space between two screens or perforated gratings vertically separated from each other by a gap clearance, during the construction of the sorption unit SE. Here the two screens are arranged at the predetermined vertical distance from each other and parallel and congruently to each other in the horizontal plane. Here each screen is constructed essentially with a plane or level surface. All round their outer circumference at their outer edges, both screens are enclosed or enveloped by the outer shell of the housing BEH as the outer boundary. The sorption unit SE is therefore arranged in the housing BEH in an essentially horizontal plane. In this way the sorption unit is preferably delimited or covered by at least one screen or grating at each air inlet opening and/or air outlet opening so that sorption material particles, in particular zeolite particles are prevented from falling out of the container BEH of the sorption unit SE and at the same time air can flow through the inside of the sorption material from the air inlet opening to the air outlet opening, largely with little flow resistance. The sorption unit preferably has a largely plane-surface input-side inflow surface and largely plane-surface output-side outflow surface. In a practical way such a sorption unit facilitates compact support for the sorption material with adequate air penetration, so that for a sorption cycle the sorption material can adequately absorb moisture from the through-flowing air by condensation and for a desorption cycle for the regeneration of the sorption material also again release or desorb stored moisture to through-flowing air by heating.

The housing BEH of the drying device TE is formed and positioned underneath the base of the washing compartment GS so that it can be penetrated by an essentially vertical airflow. That means that it allows the direction of the draft through its integrated sorption unit SE to run from bottom to top. For the air supply, the downwards-flow end section of the inlet-side tubular section RA1 of the air ducting channel VK joins the housing BEH in the region of the bottom or base of its housing. Here in the exemplary embodiment the downwards-flow end section of the inlet-side tubular section RA1 runs essentially in a horizontal plane to the bottom of the housing BEH. At the same time it is installed close to the bottom of the housing BEH. It is coupled essentially close to the bottom of the housing BEH in such a way that an airflow conveyed to it is deflected, in this case by approximately 90°, from an original, approximately horizontal through-flow direction LS into an approximately vertical through-flow direction VS through the housing BEH. Generalizing, an airflow LS arriving at the inlet-side tubular section RA1 is deflected from its original inflow direction in the region close to the base or in the bottom region of the chamber of the housing BEH into its through-flow direction VS. In this connection, the through-flow direction VS through the housing BEH is, in particular, a flow direction which flows through the housing in essentially a straight line from the closed base of the housing to a top-side outlet opening or to an outlet connector in the top of the housing BEH—here essentially in the vertical direction—to which the upwards-flow end section of the outlet-side tubular section RA2 of the air ducting channel GS is connected. With such a through-flow direction the approximately horizontally supported layer with the sorption material in the sorption unit SE is penetrated or infiltrated essentially vertically by an airflow which is being drawn through.

For desorption of the reversibly dehydratable sorption material, in particular zeolite ZEO, of the sorption unit SE, at least one heating element HZ is provided in the housing BEH in the near zone in front of the entry area of the sorption unit SE, in order to provide air heating for the sorption material SE. Here the heating element HZ is positioned in a plane in front of the entry area, from which this plane has a predetermined gap clearance to avoid local overheating of the sorption material at its inlet surface, and runs essentially parallel to said inlet surface. The heating element HZ is preferably formed by a heater bar or a heater coil. In particular, the respective heating element HZ extends essentially over the entire clear width of the entry cross-sectional area of the sorption unit SE with the reversibly dehydratable desiccant. This makes it possible to also heat the airflow in the region of the longitudinal walls extending towards the bottom, that is to say in particular to the side edges of the sorption unit SE, exactly as in the central region of the cross-sectional width of the sorption unit SE. Consequently, local moisture spots in the desiccant, in particular in the region of the side walls of the sorption unit SE, are largely avoided during desorption, that is to say uniform drying of the sorption material can be guaranteed. If the width of the sorption unit SE corresponds essentially to the internal width of the housing BEH of the drying unit TE, this heating element HZ preferably runs in front of the entry cross-sectional area of the sorption unit, essentially over the entire internal width of the housing BEH. In order to be able to heat the entry cross-sectional area of the sorption unit SE for desorption of its volume of sorption material over as large an area as possible, and therefore more or less homogenously, so that local gaps in the heating of the volume of the sorption material are largely avoided, the heating element HZ is laid towards the bottom of the sorption unit, in particular the housing BEH, preferably as a wavy line or a meandering shape. The meandering windings of the heating element preferably run to and fro towards the bottom, between the two side walls of the housing BEH, over the full internal width of the entry area of the sorption unit SE. Here the windings of the heating element HZ lie in particular in approximately the same plane.

Viewed in the direction of flow, to generate a forced airflow through the air ducting channel VH, the blower GB is provided in the inlet-side tubular section RA1 upstream of the sorption unit SE of the sorption compartment BEH.

To summarize, starting from the washing compartment GS, the air ducting channel VK leads up to the drying device TE and from there back again into the washing compartment SB. The blower GB with which air is sucked out of the washing compartment SB and blown through the drying device TE back into the washing compartment, is arranged in the air ducting channel VK upstream of the drying device TE. In the sorption compartment BEH of the drying device TE, the sucked-in air is on the one hand dried by the take-up of moisture by the reversibly dehydratable sorption material contained in said sorption compartment, and on the other hand the sorption material is again dried, that is dehydrated, at specific time intervals by means of at least one heating element, in order to be made ready to again take up moisture from the air.

Advantageously, the weight of reversibly dehydratable sorption material, in particular zeolite ZEO, provided in the sorption compartment BEH, for absorption of a quantity of moisture conveyed by the air exchange, is such that the quantity of moisture absorbed by the sorption material is less than the quantity of liquid applied to the items to be washed, in particular the quantity of liquid applied in a clear rinsing step. Consequently, in terms of its weight, the sorption material in the sorption compartment BEH is adapted in such a way that it absorbs only a portion of the total quantity of liquid, which is less that the total quantity of liquid applied to the items being washed, which facilitates efficient air moisture binding with less use of sorption material. This allows a compact form of construction for the sorption compartment. At the same time, this ensures that the energy consumption for complete regeneration of the sorption material by heating by means of a heater can be reduced, as in fact only a sufficient, adapted or measured quantity of sorption material for perfect drying of the items being washed is heated up.

In particular, the weight of the reversibly dehydratable sorption material can expediently be provided in the sorption compartment such that the quantity of moisture absorbed by the reversibly dehydratable sorption material corresponds essentially to the quantity of wetting with which the items being washed are wetted at the end of the clear rinsing step. In this case the wetting quantity, in particular, is the amount of liquid which at the end of a clear rinsing step in which the already washed items were treated with water displaced by surfactant, adheres to the washed items, the basket for holding the dishes and/or the inner walls of the washing compartment and does not flow away under gravitational force to the base of the washing compartment. This adaptation of the weight of sorption material results in its moisture absorption capacity being sufficient to more or less completely bind or take up this wetting quantity in the sorption material by means of the air exchange.

Preferably, the weight of sorption material placed in the sorption compartment is such that the amount of moisture absorbed corresponds to between 4% and 25%, in particular 5% to 15% of the amount of liquid applied to the items being washed.

Advantageously, a weight of between 0.2 kg and 5 kg, in particular between 0.3 kg and 3 kg, preferably between 0.5 kg and 2.5 kg of reversibly dehydratable sorption material is present in the sorption compartment. 

1-13. (canceled)
 14. A dishwasher, comprising: a washing compartment; a drying device to dry washed items, the drying device having a sorption compartment to hold reversibly dehydratable sorption material; and an air-guiding air ducting channel between the drying device and the washing compartment to generate an air exchange between the washing compartment and the sorption compartment; wherein, in the sorption compartment, a weight of the reversibly dehydratable sorption material that is provided to absorb a moisture quantity conveyed by the air exchange is such that the moisture quantity absorbed by the reversibly dehydratable sorption material is less than a liquid quantity applied to items to be washed.
 15. The dishwasher of claim 14, wherein the dishwasher is a household dishwasher; wherein the reversibly dehydratable sorption material is zeolite; and wherein the liquid quantity is liquid quantity applied in a clear rinsing step.
 16. The dishwasher of claim 15, wherein the weight of the reversibly dehydratable sorption material in the sorption compartment is such that the moisture quantity absorbed by the reversibly dehydratable sorption material corresponds essentially to a wetting quantity with which the items to be washed are wetted at the end of the clear rinsing step.
 17. The dishwasher of claim 14, wherein the moisture quantity that is absorbed is between 4% and 25% of the liquid quantity applied to the items to be washed.
 18. The dishwasher of claim 17, wherein the moisture quantity that is absorbed is between 5% and 15% of the liquid quantity applied to the items to be washed.
 19. The dishwasher of claim 14, wherein the weight of the reversibly dehydratable sorption material in the sorption compartment is between 0.2 kg and 5 kg.
 20. The dishwasher of claim 19, wherein the weight of the reversibly dehydratable sorption material in the sorption compartment is between 0.3 and 3 kg.
 21. The dishwasher of claim 20, wherein the weight of the reversibly dehydratable sorption material in the sorption compartment is between 0.5 kg and 2.5 kg.
 22. The dishwasher of claim 14, wherein the washing compartment has a base, and wherein the sorption compartment is accommodated in a base assembly underneath the base of the washing compartment.
 23. The dishwasher of claim 14, wherein the washing compartment has an outlet and an inlet, and wherein the drying device is connected via the air-guiding air ducting channel to the outlet and the inlet of the washing compartment.
 24. The dishwasher of claim 23, wherein, to a predetermined extent, the air-guiding air ducting channel is arranged outside the washing compartment.
 25. The dishwasher of claim 14, wherein the air-guiding air ducting channel has an outlet-side tubular section that is connected to an inlet of the washing compartment in a region close to a base of the washing compartment.
 26. The dishwasher of claim 14, wherein the air-guiding air ducting channel has an inlet-side tubular section that is connected to an outlet of the washing compartment above a base of the washing compartment.
 27. The dishwasher of claim 26, wherein the inlet-side tubular section is connected to the outlet of the washing compartment in a region near the top of the base of the washing compartment.
 28. The dishwasher of claim 26, wherein the inlet-side tubular section of the air-guiding air ducting channel enters the sorption compartment of the drying device in a region near the base of the washing compartment in such a way that an inflow direction of the air-guiding air ducting channel is deflected into a through-flow direction of the sorption compartment.
 29. The dishwasher of claim 28, wherein the inflow direction is deflected by approximately 90°.
 30. The dishwasher of claim 14, wherein a blower that generates airflow is provided upstream of the drying device when viewed in flow direction of the airflow.
 31. The dishwasher of claim 30, wherein, viewed in the flow direction, an associated heating element for desorption is provided between the blower and the drying device.
 32. The dishwasher of claim 14, wherein in the sorption compartment, when viewed in flow direction, a heating element is provided upstream of a sorption unit that contains the reversibly dehydratable sorption material for desorption of the reversibly dehydratable sorption material, and wherein the heating element is part of the sorption compartment. 